The molten region melts impure solid at its forward edge and leaves a wake of purer material solidified behind it.

[3][4][5] In addition, LHPG is a crucible-free technique, which allows single crystals to be grown with high purity and low stress.

[6][7] However, single-crystal fibers must have equal or superior optical and structural qualities compared to bulk crystals to substitute for them in technological devices.

[11] This condition generated a high radial thermal gradient in the molten zone, making the process unstable.

This optical element converts the cylindrical laser beam into a larger diameter hollow cylinder surface.